Hydrostatic fuze



Sept. 9, 1958 J. MENA Y vlEYRA DE ABREU 2,850,974

HYDROSTATIC FUZE v Filed Oct. 24, 1955 Sheets-Sheet 1 INVENTOR Tos: MENAy `Vrr- YRA ne AeReu ATTORNeYs sept. 9, 195s J. MENA Y vlEYRA DE ABREUHYDRo'sTATIc FuzE 2 Sheets-Sheet 2 Filed Oct. 24. 1955 2,850,974i'yatented Sept. 9, 1958 HYDROSTAHC FUZE Jos Mena y Vieyra de Abreu,Madrid, Spain Application October 24, 1955, Serial No. 542,450

f Claims priority, application Spain November 10, 1954 7 Claims. (Cl.102-7) VThe present invention relates to a new fuze applicable tounderwater projectiles and particularly to depth charges for use againstsubmarines.

This fuze will ensure an underwater explosion of the projectile or thedepth charge, with such precision as to the calculated depth, that itsabsolute and relative errors are technically insignificant.

The mechanisms thereof operate in combination with a` normal hydrostaticpressure. Provision is made to prevent detonation due to an abruptexcess of pressure, so that the explosion of other mines exercise noeffect on their correct performance.

Furthermore, provision has been made to block all mechanisms in order toprevent their performance until the charge has reached a predetermineddepth of, for example meters, thereby avoiding all risks to any craftlaunching such devices.

The novel fuze is likewise provided with all safety devices required ofthis kind of projectile, both for their storage as also for thetransport and manipulation thereof.

These safety devices by no means interfere with the perfect performanceof the apparatus and are achieved by a very reduced number of procientlyarranged elements, whereby within a few seconds, the entire mechanismcan be removed from the depth charge for an inspection thereof.

The desired depth can be set instantaneously, or changed at will, eitherto increase or reduce the depth of explosion. Said regulation of depthcan be performed within a few seconds and set as often as required.

It will be understood that with this device, technically, there is noneed to limit the maximum depth of explosion, as all elements canoperate at any depth. In practice, its use is generally confined to themaximum depth apt to be reached by a submarine.

Moreover, absolute .watertightness has been provided for, therebypreventing deterioration of the mechanism and explosive charge.

For a better comprehension of the invention, the accompanying drawingsrepresent, in:

Fig. 1, a longitudinal section of the fuze;

Fig. 2 shows a perspective view of the depth setting and indicatordevice;

Fig. 3 shows the spring compressor element;

Fig. 4 shows a perspective view of the uted sleeve;

Fig. 5 shows a development of the lower portion of the compressorelement shown in Fig. 3;

Fig. 6 shows a partial view of the sleeve which externally sheathes thatportion of the fuse showing the depth marked by the indicator;

Fig. 7 shows a plan view of the graduated index disc;

Fig. 8 shows a sectional view of the safety device between the primerand the booster; and

Fig. 9 shows a sectional view of the device shown in Fig. 8 at the timethe fuze operates.

The fuze body 22, Fig. l, is constituted by a cylindrical element theupper portion of which has an externally threaded central shank 22a towhich is screwed a depth regulator. Underneath the depth regulator is acircular flange 22b for the accommodation of a dual setting disc 12 andon which is a threaded ring 22C to which is threaded a cap 1. The fuzebody is threaded at 22d to hold the fuze in the projectile casing. Thellange 2211 is turned by a wrench the teeth of which engage with severalholes 22e. Between the flange and the projectile casing may be placed aresilient gasket of rubber or other appropriate material for insuring awatertight joint. Within the fuze body 1 is an axial cylindrical bore22f within which is slidably mounted a tube 5. The bore 22j is enlargedwithin the shank 22a to accommodate locking balls 36 which are set inholes in the end of tube 5.

An expansion chamber 42 is provided within fuze body 22 and is closed bya gasket 43 which is held in place by a washer 44.

A cylindrical casing 23 is threaded to the end of fuze body 22, andwithin the lower end of the cylindrical casing 23 is threaded a flutedtube 45 having flutes 16 on the outside thereof. At the end of thefluted tube 45 within the cylindrical casing 23 is a groove 46.

Attached to the tube 5 is a sleeve 4, which extends within thecylindrical casing 23 and the end of which surrounds the grooved end ofuted tube 45. The sleeve 4 together with the tube 5 forms a springcompressor element. On the inside of the end of sleeve 4 surrounding theuted tube 45 are two wedges 15 which project into the groove 46.

Sleeve 4 has a plurality of apertures in the wall thereof which arespaced both circumferentially and axially from each other along theentire length of the sleeve. In the embodiment shown, two sets ofapertures are provided, one aperture in each set having a diametricallyopposed aperture in the other set.

Within the end of the fluted tube 45 is slidably fitted a primer piston19, in the upper end of which is a pair of diametrically opposed slots18a. Fluted tube 4S has a pair of diametrically opposed apertures 46a inthe end thereof within the sleeve 4, and positioned within theseapertures are locking detent balls 18 which project into the grooves 18aon the primer piston 19. On the end of the primer piston 19 is a primercasing 20 within which is a primer 21 and a detonator cap 7.

A spring 6 is provided between the end of the sleeve 4 attached to thetube 5 and the primer piston 19. In the position of the parts shown inFig. l, the spring is unstressed.

Threaded into the end of the fluted tube 45 where it is attached to thecylindrical casing 23 is a cap 39 within which is a safety device to bedescribed below. Threaded into the cap 39 is a booster casing 27containing a booster charge 26 having an axial bore 26a therein. Withinthe axial bore 26a is a ring pin 8 which is pointed toward the primer21.

The depth setting device comprises an inner adjusting member 11 which isthreaded over the shank 22a and which has the tube 5 projectingtherethrough. At the point where the tube 5 passes through the inneradjusting member 11, the outside diameter of the tube 5 is reduced sothat when inner adjusting member 11 is screwed onto the shank, tube 5will be moved into the fuze body 22.

Over the inner adjusting member is a cover member 9 which is rotatablymounted on the inner adjusting member 11, and which has dependingtherefrom dual pointers 10 which extend downwardly to the fuze settingdisc 12. Through the cover member 9 is a diametrical bore 13a, and inthe end of the tube 5 are two apertures 14 which may be aligned with thebore 13a. A safety pin 13 may be inserted through the bore 13a and theapertures 14, and held therein by the arm 13b.

In the cap 1 are two Valves 29 each consisting of a housing 2, 3 havingan aperture 30 on the inner end thereof, and having a spring loaded plug31 therein which is spring loaded outwardly by spring 32.

Within the ,upper end of tube ,5 is a gland 33. Adjacent the lower endof gland 33 are a plurality of grooves 35 in the tube 5. Gland 33 has atransverse bore therethrough within which are mounted spring ,loaded:balls 34 which are spring loaded outwardly Aand which :normall-y engagein 'one -of the grooves 35.

.In -the ,cap '39 threaded into the lower end of iluted tube 45 isaztransverse passage 28a within which are ytwo rollers 28 held in placeyby spring loaded balls 38 .engaging in a groove l40 yalong the wall oflpassage 23a. The rollers 28 are normally in contact with each other asshown in Fig. 8.

In the lwall fof Ythe `cylindrical casing 23 adjacent the end-of sleeve4 is an opening 24, and depth setting corresponding to the settings onthe fuze setting vdisc '12 are printed 'on the end of sleeve 4 on alevel with the opening 24.

The number of spaces between the utes V-16 Alon'fluted tube 19 is onegreater than the ynumber oftpairs of Aopposed apertures 17. Thespacingof the y'flutings is such that the spaces between them arevertically aligned with the apertures `17 'in the sleeve 4.

As the hydrostatic pressure yoperates upon the com-V pressor `element 4,5, it is caused to descend, Icompressing the spring 6, which thusaccumulates sufficient force :to re the Vprimer 7, which upon Vstrikingthe firing pin y8, produces the explosion. 'The ldepth at which lthisdetonation is to `be produced, is set by Vmeans lof `the depth settingdevice. ABy the rotation of said pointers -1'0'to 'mark the desireddepth on the graduated disc, the compressor element 4, 5 is also causedto rotate, as pin 13 'engages the tube 5 andthe casing9, thus placingthe vtwo internal wedges at the lower end of the lcompressor element sothat they Vwill register with the entrance of` two ofthe flutes on thetinted sleeve `45. This will cause .the compressor element to descendAin the axial direction b y the sliding action of said wedges in thereferredk toutes or channels.

The locking `detent balls 18 provided in the `openings in the upperportion of the fixed fluted sleeve 4'5prevent a descent of the primerpiston '19 until they escape. The spaces between flutes `16` in thefluted sleeve 45 are arranged in such la manner that the balls 18 willregister with that pair of openings '17 that has been aligned therewithby the fuse setting device, which openings lare placed at a 'higherposition in the sleeve 4 the greater the `depth at which the detonationof the charge is required.

'To set the explosion depth, the cap 1 is removed temporarily in orderto rotate the cover member 9 on .the depth setting device `in thedesired direction so that the two pointers 1t! thereof will coincide onthe graduated disc 12, with the desired detonation depth. Whilemaintaining -said cover member 9 in .this position, the internal element11 of the depth setting device is screwed down, whereby the compressorelement is immobilized, since the two wedges 15, which .heretoforerotated freely inthe slot 46, see Figs. ,l and 4, will have entered twochannels on sleeve 45.

Thereafter, by removing ytherpin 13 and replacing the cap 1, the fuse isprepared to operate underthe influence of hydrostatic pressure.

After Ahaving set the depth at which the explosion ris to occur, thecharge is ready for launching. As the charge enters the water, thehydrostatic pressure is increased, thereby opening the valves v31, soAthat the water will fill the interior of the cap 1 and penetratethrough the bores previously occupied by the `pin 13 to the -tubularsleeve 5 where it will meet with Vthe resistance of the gland 33 thatcloses said tube.

Assoon as thecharge Areaches eight or ten meters, but not before, thewater pressure will be able t-o -push `said gland 33 inwards to overcomethe predetermined `resistance of the two-spring loaded balls 34 againstfthe `inner walls :of =the ltubular sleeve -5 in -which successiveldetention slots 35 are provided. By -this safety feature, the

mechanisms are kept blocked, preventing their performance, while thecharge reaches a minimum depth of eight or ten meters, or any otherpredetermined depth, so that under no conditions the charge can explodein the proximity of the launching craft.

While the gland 33 occupies the position shown in the drawing, or withthe two balls 34 held in any of the successive slots 35, Vthe tube y5cannot descend, the balls 36, lodged in the walls of said shank beingpushed outwardly :by the `gland 33 land protruding a `suiicient distanceinto .slots -47 to prevent the descent.

After the water has pushed the gland 33 to the bottom of thetube- 5 the-balls 36 wil-l offer no further resistance, as they will now fall intotube 5.

By the progressive advance of the compressor element, the spring 6 willbe compressed until the two bores 17 situated vertically above the twoballs 18 register therewith, at which moment the balls 18 escape.:Piston 19 is then free and yis then impelleddownward by lthe spring. Atthis moment, the primer tube 20, "forming ,a conical wedge, willpenetrate bet-Ween the rollers 28, `see Fg..8, and ythus advance untilthe primer ,strikes against `the point 'of 'the lfiring pin l8, see Fig.9, -thereby causing an explosion in the very center of the booster 26.

The two -rollers 28, see Figs. -8 and =9, placed in lparallel and "in'contact with each other, serve as a-safety device to 4break the shockwave, liable to be produced by an untimely explosion 'of the primer 7.Fig. -8 shows 'the position lof said rollers 28 prior to theirseparation by the conical lpoint Aof the primer tube 20, and Fig. Y9shows said rollersv after their separation, thus permitting the'passageof the primer `tube 20'toward the firing-pins. The rollers 28 lare heldin contact by la Vslight Vpressure of the spring 37, whichcompresses theballs 38 against the walls of the lower plug 39, which is in turn`providedgwith slight cavities 40 on the internal walls thereof.

The pin 13, which transmits the rotation Iof the indicator 9 to the tube5, likewise constitutes asafety-device, since .while it is xedin itsnormal position it will prevent a descent of the compressor element, theupper end of whichis traversed by the pin 12 which has to beremovedbefore the device will operate. The flutes 16 tend to keep the balls 18aligned with the'V selected pair of bores 17 for each depth. However,there is a pair of .flutes that do not coincide with `any pair of bores,so that by placing the indices '10 on the cap 9v of depth setting device411 in the position marked with the thick line 41, the fuze cannotoperate, since the wedges 15 register precisely with the onlyvpair offlutes `1`6 that do not permit balls18 to coincide with anyof the 'bores17.'

If a small amount of Watershould penetrate between the compressorelement and the fuze body '22, a cavity 42 has been provided wherein it-will'be retained `by means of Ia resilient gasket 43, which iscompressed 'by the threaded washer 44.

If, after the charge hasY been launched, an abrupt excess of pressureshould occur, for example, from another mine or depth charge, the plugs31 inthe valves 29 would then descend to the bottom overcoming theresistance of their springs 32, .and thus closing the bores 30andpreventing :the passage of water pressure into the fuze.

l. A hydrostatic fuze for use in underwater explosive devicescomprisinga fuze body engageablejn lthe explosive device and -having anaxial bore therethrough, a ,cylindrical casing attached to one .end .ofsaid -fuze body, a spring compressor element having a tube slidable inysaid bore and a sleeve fixed to the endof said` tube within saidcylindrical casing, said sleeve having aplurality of apertures in thewall thereof spaced circumferentially and axially of said sleeve fromkeach other, a wedge on the end of said sleeve opposite said tubeprojecting radially into said sleeve, a utedftube attached within .theend of said cylindrical casing opposite said fuze body and `extendingwithin the Vend `of saidsleeve, said .fluted tube havingwa groove aroundthe outside of the end thereof within said sleeve into which said wedgesproject, each of the utings being vertically aligned with one of saidapertures in said sleeve, a detent locking ball in the end of the wallof said n uted tube within said sleeve, a primer piston slidable Withinsaid iluted tube having a groove therein in which said locking detentball is engaged, a spring between said primer piston and said sleevenormally in the unstressed Condition, a primer on the end of said primerpiston opposite said spring, a booster having an axial bore thereinattached on the end of said cylindrical casing with the bore alignedwith said primer, a firing pin in said bore, means between said primerpiston and said booster for blocking a shock from the explosion of saidprimer and for permitting passage of said primer, depth setting means onthe end of said tube opposite said sleeve for rotating said tube andsaid sleeve and for urging said tube and sleeve toward said primerpiston, gland means held in the end of said tube adjacent said depthsetting means for keeping water pressure from within said tube until apredetermined pressure has been reached, and a cap over said depthsetting means having a valve therein for admitting water to said fuze. j

2. A hydrostatic fuze as claimed in claim 1 in which said means betweensaid primer piston and said booster comprise a pair of spring loadedrollers in contact with each other, a plug in the end of said uted tubehaving openings therein in which said rollers are movable, and the endof said primer being beveled.

3. A hydrostatic fuze as claimed in claim 1 in which said depth settingmeans comprising an inner adjusting member threaded to said fuze body, acover member rotatably mounted on said inner adjusting member and havingpointer means thereon and a bore therethrough, said tube havingapertures therein in alignment with said bore, and a pin through saidbore and apertures.

4. A hydrostatic fuze as claimed in claim 1 in which l said gland meanscomprise a gland slidably tted in the interior of'said tube having agroove therein, and a spring 6 loaded locking ballin said opening insaid gland and projecting into said groove.

5. A hydrostatic fuze as claimed in claim l in which all but one of theflutings on said fluted tube are aligned with one of said apertures inthe wall of said sleeve.

6. A hydrostatic fuze as claimed in claim 1 in which said valves in saidlcap having a spring loaded plug therein are spring loaded outwardly,and yhave an aperture beneath said plug, whereby a sudden hydrostaticpressure causes the plug to overcome the spring loading and close saidaperture.

7. In a hydrostatic fuze for use in underwater explosive devices havinga fuze body engageable in the explosive device and having `an axial moretherethrough, the combination of a cylindrical casing attached to oneend of said fuze body, a spring compressor element having a tubeslidable in said bore and a sleeve fixed to the end of said tube Withinsaid cylindrical casing, said sleeve having a plurality of apertures inthe wall thereof spaced circumferentially and axially of said sleevefrom each other, wedges on the end of said sleeve opposite said tubeprojecting radially into said sleeve, a iluted tube attached within theend of said cylindrical casing opposite said fuze body and extendingwithin the end of said sleeve, said fluted tube having a groove aroundthe outside of the end thereof within said sleeve into which said Wedgesproject, each of the flutings being vertically aligned with one of saidapertures in said sleeve, a detent locking ball in the end of the wallof said fluted tube within said sleeve, a primer piston slidable withinsaid fluted tube having a groove therein in which said locking detentball is engaged, and a spring between said primer piston and said sleevenormally in the unstressed condition.

References Cited in the file of this patent UNITED STATES PATENTS1,514,743 Taylor Nov. 11, 1924 FOREIGN PATENTS 165,108 Great BritainJune 3o, 1921

